Prosecutors describe the campaign as an act of genocide against the Kurdish people, while the former Iraqi government defended its actions as a necessary counter-insurgency operation during wartime.

Although estimates vary, it is believed that around 182,000 Kurds were killed during this period, and more than 3,000 villages destroyed.

The Iraqi High Tribunal announced in April last year that Saddam and six co-defendants -- including Ali Hassan al-Majid, also known as Chemical Ali -- would face charges of genocide over the Anfal campaign.

Saddam, however, was executed on December 30 for crimes against humanity in a separate case, following which Majid has emerged as the star defendant in the Anfal trial.

On Sunday, the Iraqi High Tribunal will issue its verdict against the remaining six accused.

Between 1987 and 1989, Kurds suffered a series of major attacks -- including a gas attack against the town of Halabja in 1988 in which 5,000 people died.

The Halabja massacre is not included in the current case, however.

The gassing of Halabja, allegedly by Iraqi forces, followed the town's capture by Kurdish peshmergas (warriors) backed by Iranian revolutionary guards.

The term Anfal comes from the eighth sura of the Koran and means spoils. The campaign reportedly involved the systematic bombardment, gassing and assault of areas in the Kurdish autonomous region in 1988.

By 1986, with the regime under severe strain owing to its 1980-88 war with Iran, large swathes of the Kurdish region had become free of central government control.

In 1987, Saddam charged "Chemical Ali," who is his cousin, with bringing the area back under state control.

Ali began by declaring "prohibited" zones, much like the Vietnam war-era free-fire zones, in which all inhabitants were considered insurgents.

Villagers were moved to defined and easily controlled settlements, while the prohibited areas were shelled and then invaded in classic counter-insurgency tactics.

According to the New York-based Human Rights Watch, what made these campaigns different from other counter insurgency operations was a clear plan to exterminate the Kurds as a people.

"Tellingly, the killings were not in any sense concurrent with the counter-insurgency: the detainees were murdered several days or even weeks after the armed forces had secured their goals," the organization said in an extensive report on the campaign before the start of the trial.

"Finally, there is the question of intent, which goes to the heart of the notion of genocide," said the report, which provided detailed documents and testimony to support its view.

And on Friday the organization said the 10-month old trial was marred by errors.

Central to the case is Majid, and accusations that he made liberal use of poisonous gas, mass executions and prison camps to subdue the north.

The other defendants include former defence minister Sultan Hashim al-Tai and high-ranking Baathists Sabir al-Duri, Hussein Rashid al-Tikriti, Taher al-Ani and Farhan al-Juburi.

The six defendents face the gallows if convicted.